PHYLUM PROTOZOA 



*5 



In some of the Coccidiidea this life cycle is modified in various ways, as, for 

 example, by the omission of schizogony — the trophozoites in such a case 

 developing directly into gametocytes. 



Flo. 65. — Life-History of Coccidium tchubergi. a. penetration of epithelium cell of host by 

 sporozoite; b-c, stuges of multiple fission (schizogony); d, gametocyte ; t, f, formation of 

 megagamete (ovum) : g, fertilisation ; h, j, formation of microgamctes (sperms) ; h, develop- 

 ment of fertilised ovum into four spores ; I, formation of two sporozoites (falciform young) in 

 each spore. (From Calkins, after Schaudinn.) 



Order 3. — H^mosporidea. 



These are Sporozoa which in the trophozoite condition live as parasites in 

 the interior of the coloured blood -corpuscles of all classes of Vertebrates, but 

 are occasionally found in other cells. In Man and in some other mammals and 



